Vein patterns being biological information are in-vivo information, so that forgery thereof is difficult. In addition, the vein patterns are not determined by human genetic information (base sequences of DNA), so that even identical twins mutual with the same genetic information each have different vein patterns, thereby enabling discrimination therebetween. Thus, individual identification based on vein patterns has high identification accuracy.
Mechanism of individual identification based on finger vein patterns will be outlined. When a finger is irradiated with near-infrared rays, the near infrared rays passing through the inside of the finger are easily absorbed by hemoglobin flowing in finger veins. Because of this, when the finger is irradiated with near-infrared rays and light passing through the finger is imaged, finger vein patterns appear as black shadows. Thus, for identification, a reading unit images transmitted light through the finger, and a vein identification unit extracts vein patterns from imaging information. Then, the extracted vein patterns and vein patterns preliminarily recorded in the database (identification data) are compared with each other to perform individual identification.
In an individual identification apparatus based on vein patterns, a reading unit has an inner surface on which a specific person's finger is disposed and in which a light source such as a light emitting diode (LED) or the like is disposed, and another inner surface facing the LED in which a charge-coupled device (CCD) image sensor is disposed. Other than the CCD image sensor, a two-dimensional photosensor such as a complementary metal oxide semiconductor (CMOS) image sensor is available. The LED emits light and the light passes through a finger. Then, the CCD image sensor or the like captures a transmitted light image of vein patterns to convert it into a digital signal. When a database has corresponding identification data, the identity of the person is recognized.
Individual identification using facial information being biological information is usually performed by individuals in normal social life, and thus identification using facial information is a customary identification method. Meanwhile, undergoing facial identification enables a fraud user to be easily identified for unfair use, on the basis of facial information, and awareness that facial information may be recorded gives a psychological effect of preventing fraud to a test subject.
An individual identification apparatus based on facial information includes a camera for imaging a face, and a facial identification unit having a database for preliminarily recording facial identification data. When receiving imaging information from the camera, the facial identification unit extracts facial information from the imaging information and checks the extracted facial information with facial identification data to perform identity verification. Japanese Patent Application Laid-Open (JP-A) No. H05-46743 (Patent Literature 1) discloses a specific example of an individual identification apparatus based on facial information. The individual identification apparatus disclosed in Patent Literature 1 includes an image input unit (camera) that obtains imaging information of a face and gives the imaging information to a facial information extraction unit (feature point extraction unit). The facial information extraction unit extracts facial information (position information of feature points such as eyes, nose, mouth, etc.) from the imaging information. Meanwhile, a database preliminarily stores facial identification data (position information of feature points) of a test subject. Then, a difference detector obtains difference information from the facial information (coordinate values of respective feature points) extracted by the facial information extraction unit, and the facial identification data (coordinate values of respective feature points) stored in the database. Then, a processing unit performs individual identification on the basis of the difference information and the like.